To produce a superconductor cable, a superconducting cable core is produced and subsequently drawn into a cryostat, or the superconducting cable core is enveloped by the individual components of the cryostat in a continuous operation.
In the production of the superconductive flexible cable core, first a multiplicity of superconductive strips are laid around a strand of copper wires with a relatively great length of lay. Subsequently, a number of layers of insulating material in strip form are laid onto the layer of superconductive strips. Generally, strips of paper or strips laminated with plastic are wound onto the layer of superconductive strips. Over this layer of insulating material, the shielding is applied, comprising at least one layer of superconductive strips, which are wound onto the insulating layer with a great length of lay. Over the outer superconductive layer there is also a layer of copper strips.
A superconductor cable arranged in a cryostat is known for example from DE 102 21 534 A1. Since the production of the superconductor cable and its enclosure in the cryostat are performed at room temperature, but the operation of the superconductor cable takes place below the transition temperature of the superconductive material, a contraction of the superconductor cable takes place while it is cooling down, for example, when cooling down from 300 K to 77 K, a contraction of about 0.3%. In the case of a cable length of, for example, 600 m, consequently the contraction of the cable core is, for example, 1.8 m.
A problem therefore arises, inasmuch as it is necessary to compensate for the contraction occurring during the cooling down by means of an excess length of the cable core, since otherwise strong tensile forces would be exerted by the cable core and could lead to it being damaged.
To solve this problem, it is known from DE 10 2004 019 141 to draw a superconductive cable core off from a supply, envelop the cable core with a longitudinally running-in metal strip, shape the metal strip into a tube, weld the longitudinal edges and corrugate the welded tube, the inside diameter of the corrugated tube being greater than the diameter of the cable core. The cable core and the corrugated metal tube are then wound up onto a cable drum. The ends of the cable core are mechanically connected to each other at the ends of the corrugated tube while the cable core and the corrugated tube are located on the cable drum. On account of the rigidity of the cable core, during winding-up it comes to bear against the inside wall of the metal tube outside it, i.e. the cable core has the tendency to assume the greatest possible winding diameter, whereby the excess length of the cable core with respect to the metal tube is produced.